Which LoW principle states even where one is justified in acting, one must not act in a way that is unreasonable or excessive?

• A. Proportionality
• B. Humanity
• C. Distinction
• D. Honor

Answer: (A)

Proportionality governs how much force is allowed in pursuit of a legitimate military objective. Even when action is justified, the means used must be no more extensive than necessary to achieve that objective. The key test is a balance: the expected concrete and direct military advantage weighed against the potential civilian harm and damage to civilian objects. If the anticipated civilian harm is excessive in relation to the military gain, the act is not permitted. This keeps military action from becoming an overwhelming or disproportionate response in comparison to what is being achieved.

For example, striking a target that yields a moderate military advantage but would cause massive civilian casualties would be disproportionate, whereas a targeted, precise action that achieves the objective with minimal collateral damage would fit. Other LoW principles guide other aspects—distinction focuses on targeting civilians versus combatants, and humane treatment concerns how people are treated, while honor is not the specific constraint in this balancing test.